1. Field Of The Invention
The invention relates to a process for the production of aminomalonic acid dinitrile.
2. Prior Art
It is known to isolate aminomalonic acid dinitrile as the p-toluene sulfate by reduction of oximinomalonic acid dinitrile with aluminum amalgam. This production, however, is time consuming and cumbersome. The amalgamation of the aluminum causes difficulties, since the mercury layer on the surface of the aluminum does not adhere well. Moreover, during sucking off of the aluminum hydroxide after the reduction, much of the product remains behind in the deposit (precipitate) (J. P. Ferris, L. E. Orgel, J. Am. Chem. Soc. 87, 4976-7 (1965); J. P. Ferris, L. E. Orgel, J. Am. Chem. Soc. 88, 3829-31 (1966); J. P. Ferris, U.S. Pat. No. 3,670,007 (1972), C. A. 77, 100866v (1972); J. P. Ferris, R. A. Sanchez, R. W. Mancuso, Org. Synth. 48, 1-3).
In U.S. Pat. No. 3,670,007, it is also disclosed that oximinomalonitrile or phenazomalonitrile can be reduced with zinc, sodium or aluminum dithionite in the presence of acid to form aminomalonitrile. However, the process is limited to the quantitative proof of aminomalonic acid dinitrile in the reaction solution.